This invention relates to a method of treating a fibrous substrate so as to alter its chemical and/or physical functionality.
The substrate may, for example, comprise fibres or a fabric.
The present invention further relates to the use of the method aforesaid to enhance the receptivity of a fibrous substrate to dyes.
The present invention yet further relates to the use of the aforesaid method to enhance the adhesion, to a fibrous substrate, of other materials.
In a first aspect, the present invention provides a method of treating a fibrous substrate so as to alter its chemical and/or physical functionality, in which the substrate is reacted with an aqueous solution of a polymer comprising at least one phosphono-component or at least one phosphono-component selected from the group consisting of:
(a) monomeric or homopolymeric vinylidene-1,1 diphosphonic acid (VDPA);
(b) homopolymeric vinylphosphonic acid (VPA);
(c) a copolymer of VPA or VDPA with an unsaturated sulphonic acid, an unsaturated carboxylic acid, an unsaturated amide, a primary or secondary amine or a polyalkylene imine;
(d) a terpolymer of VPA or VDPA with two components selected from unsaturated sulphonic acids, unsaturated carboxylic acids, unsaturated amides, primary or secondary amines and polyalkylene imines;
(e) the reaction product of VDPA and a primary or secondary amine, a polyalkylene imine or hypophosphorous acid or the salts of said acid; and
(f) a phosphono-substituted monocarboxylic or dicarboxylic acid.
For example, the phosphono-componentmay comprise phosphono-succinic acid.
For example, the polymeric composition may consist essentially of a copolymer of vinylphosphonic acid (VPA) with vinylsulphonic acid (VSA), or with acrylic acid (AA), methacrylic acid (MAA) or acrylamide.
Alternatively, the polymeric composition may consist essentially of a copolymer of VDPA with VSA, or with AA, MAA or acrylamide.
As another example, the polymeric composition may consist essentially of a terpolymer of VDPA, VSA and either AA, MAA or acrylamide.
In a second aspect, the present invention provides the use of a method as hereinabove described to enhance the receptivity of a fibrous substrate to dyes.
Finally, the present invention provides the use of a method as hereinabove described to enhance the adhesion, to a fibrous substrate, of other materials.
Compositions according to the present invention may be applied to fibrous substrates which include cellulosic fibres. The cellulosic fibres are preferably natural cotton, but may be ramie, flax, linen, paper or cardboard or regenerated fibres (e.g. viscose or cuprammonium fibres) or partly etherified or esterified cellulose (e.g. cellulose acetate or propionate).
The substrate may contain both cellulosic and non cellulosic organic fibres, or consist entirely of non cellulosic organic fibres (e.g. 100% polyester fibres) or in some circumstances may consist entirely of cellulosic organic fibres (e.g. 100% cotton fibres).
The non cellulosic fibres are preferably polyester or polyamide, glass or carbon fibres, but may also be acrylic. The fibres may be metal or ceramic fibres. Other suitable non-cellulosic fibres include those of poly (p-phenylene benzo-bisthiazole) and poly (p-penylene benzo-bisoxazole). The polyamide may be an aliphatic one, such as copolymers of a polyaminc (such as a diamine) preferably an alkylene diamine, e.g of 4-12 carbon atoms and a polycarboxylic acid, e.g. a dicarboxylic acid, of 4-14 carbon atoms, such as an alkylene dicarboxylic acid (e.g NYLON* 66), or polylactams (such as NYLON* 6). Alternatively, the polyamide may be an aromatic one, such as an aramid based on aromatic dicarboxylic acids and phenylene diamines. The substrate can contain at least 20% of cellulosic fibres and up to 80% of coblendable fibres e.g. 10-80% especially 25-80% of coblendable fibres (such as polyamides). However, the substrate preferably comprises cellulosic fibres and polyester fibres. The substrate usually contains up to 80% (e.g. up to 70%) polyester fibres and the remainder cellulosic fibres.
Substrates comprising at least 45% non cellulosic fibres such as polyester fibres, e.g. 45-100% polyester, are preferred, as are substrates comprising 30-78% cellulosic fibres and 22-70% polyester fibres, or 30-62% cellulosic fibres and 38-70% polyester fibres. The polyester is usually a condensation product containing structural units from an aliphatic alcohol, e.g. a dihydric alcohol, especially ethylene glycol or butane diol (or mixtures thereof) and an aromatic dicarboxylic acid, e.g. terephthalic acid, or a mixture thereof with other dicarboxylic acids, such as isophthalic acid, or sebacic acid.
The substrate fibres may be in the form of thread or non woven fabrics, but are preferably used in the form of woven fabrics. Mixtures of fibres (e.g. of cellulosic and other fibres) may be an intimate or non intimate mixture, but the fibres are preferably in the form of blends of cellulosic fibres and other fibres, (e.g. polyester fibres), as in cospun blends such as cotton/polyester or polyester/cotton staple fibre, but may be in the form of core spun yarn with a core of the other fibre, e.g. polyester-sheathed cotton fibres. In a fabric, the warp and weft fibres are preferably the same, but may be different, e.g. one may be made from cotton fibres and the other from, say, polyester/cotton fibres or NOMEX*/cotton. Thus in this specification the term xe2x80x9cblendxe2x80x9d also includes unions and union/blends as well as core/sheath fibres.
The method according to the present invention may be applied to the dyeing of fibres or fabrics.
The reactive dyeing of a fibre or fabric consisting essentially of cellulose (e.g. cotton, ramie, flax, linen, paper, cardboard) or of regenerated fibres (e.g. viscose or cuprammonium fibres) or of fibres and fabrics of cellulose acetate or cellulose propionate has hitherto required the addition of inorganic salts to the dye bath to enhance the receptivity of the fabric to the dye. Such salts require removal from the spent dye bath at the conclusion of the dyeing process.
The Applicants have found that the treatment of such fibres or fabrics with polymeric compositions according to the method of the present invention avoids the need to use inorganic salts, enhances the take-up of the dye by the fibre or fabric and enables the fibre or fabric to retain more of the dye after washing.
Non-cellulosic fibres or fabrics (e.g. polyester fibres or fabrics) have hitherto had to be dyed by means of disperse dyes. Disperse dyes do not react chemically with the fabric they have to be physically xe2x80x9centrappedxe2x80x9d in the fabric by the application of elevated temperature and pressure. Thus, a reactive dye would not be expected to xe2x80x9ctakexe2x80x9d on a polyester fabric.
The Applicants have found that the use of a polymeric composition according to the method of the present invention to treat polyester fibres or fabrics results in the fibre or fabric becoming capable of being dyed by means of a reactive dye.
With regard to the dyeing of fabric blends (e.g. cotton/polyester blended fabrics), this has previously necessitated the use of two dyes : a reactive dye for the cotton and a disperse dye for the polyester.
The Applicants have found that the use of a polymeric composition according to the present invention to treat cotton/polyester blended fabrics results in the fabrics becoming capable of being dyed by means of a single reactive dye.
The use of the polymeric compositions of the present invention is equally applicable to fibres used in composites, wherein the adhesion at the interface between the fibres and the matrix is enhanced by the use of the polymeric compositions.
Such adhesion-enhancement has been evidenced by an increase in the force necessary to debond the fibres from the matrix and confirms interaction of the treated fibres, through the polymeric composition, with the matrix material (e.g. a resin). Suitable variation of the polymeric composition can be used to produce a xe2x80x9ctightxe2x80x9d or a xe2x80x9cloosexe2x80x9d composite, depending upon the desired properties of the composite.